Hot perforating mill

ABSTRACT

A hot perforating mill has a first roller guide alongside the carriage which releasably carries the piercing mandrel. A first lifting arm raises the mandrel off the first guide and holds it in position for the carriage to engage when the carriage is moved from its rearward to its forward position. When a tubular bloom has been formed and the carriage moves the mandrel, surrounded by the bloom, clear of the mill rollers, a second lifting arm moves the bloom and mandrel transversely on to a second roller guide. Here the bloom is extracted from the mandrel while the mandrel is held against movement. The bloom and mandrel travel separately down the second guide, the mandrel being transferred on to a bench behind the carriage for cooling and storage before being placed on the first guide for re-use.

llited States aterrt n91 Passoni HOT PERFORATHNG MILL Inventor: Teresio Passoni, Milan, Italy Assignee: lnnocenti Societa Generale Per Llndustria Metallurgica 8: Meccanica, Milan, ltaly Filed: Apr. 1, 1971 App1.No.: 130,366

Foreign Application Priority Data Apr. 10, 1970 Italy ..68210 N70 US. Cl. ..72/97, 72/209, 72/250 Int. Cl ..B21b 25/02, B2lb 25/06 Field of Search ..72/209, 97, 250, 252, 208;

References Cited UNITED STATES PATENTS Prieur ..72/209 X Primary Examiner-Milton S. Mehr Attorney-Sughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A hot perforating mill has a first roller guide alongside the carriage which releasably carries the piercing mandrel. A first lifting arm raises the mandrel off the first guide and holds it in position for the carriage to engage when the carriage is moved from its rearward to its forward position. When a tubular bloom has been formed and the carriage moves the mandrel, surrounded by the bloom, clear of the mill rollers, 21 second lifting arm moves the bloom and mandrel transversely on to a second roller guide. Here the bloom is extracted from the mandrel while the mandrel is held against movement. The bloom and mandrel travel separately down the second guide, the mandrel being transferred on to a bench behind the carriage for cooling and storage before being placed on the first guide for re-use.

5 Claims, 5 Drawing figures FATENTEUHARZYIUYS SHEET 10F 4 INVENTOR sw m, m wz, MN

TEKES/c BY 2: 4 MMFIQK ATTORNEYS PATENTEDHARZYIHYS SHEET 2 [IF 4 PATENTEDHARZYIHH 3 5 SHEET 4 OF 4 Fug 4 "Ill" HOT PERFORATING MILL This invention relates to hot perforating mills for forming tubular blooms.

Known mills of this kind comprise two barrel rollers with crossed axes. They engage a billet in the form of a bar, causing it to advance over a pointed mandrel which pierces the bar along its axis, transforming it into a tubular bloom.

As soon as the bloom is completely formed and surrounds the mandrel a carriage connected to the mandrel withdraws the mandrel from the bloom. The bloom is removed and the carriage is moved back into position for a new operation.

The perforating mills described above have numerous disadvantages.

Above all, since the mandrel is subjected to severe thermal stress and must be frequently changed, the mill is unproductive during such changes.

Moreover, the long movement of the carriage for withdrawing the mandrel from the bloom and the operations necessary for removing the bloom and returning the mandrel into the rolling position take a relatively long time, which limits the productivity of the mill. This lost time obviously increases with the length of the bloom.

The object of the invention is to provide a hot perforating mill in which lost times are reduced to a minimum and productivity is independent of the length of the bloom produced.

The invention provides a perforating mill for forming tubular blooms, the mill comprising at least two mill rollers arranged with crossed axes defining a space at the front end of the axis of the mill; a carriage mounted behind the mill rollers and adapted to carry a mandrel that lies along the mill axis, the carriage being movable between a forward position in which the mandrel is located in the space between the mill rollers and a rearward position in which the mandrel is located behind the mill rollers; ejecting means adapted to eject the mandrel from the carriage when the carriage is in its rearward position; with the improvement of a first guide spaced away from the mill axis and adapted to carry a mandrel a first lifting means adapted to move a mandrel fromthe first guide to a position along the mill axis for engagement by the carriage; a second guide spaced away from the mill axis and adapted to carry a bloom and a mandrel; and a second lifting means adapted to move a mandrel surrounded by a bloom to the second guide from a position along the mill axis when the carriage is in its rearward position and the releasing means has ejected the mandrel from the carriage.

From the foregoing it can be seen that the length of the movement of the carriage is always the same irrespectively of the length of the bloom. In fact, the movement of the carriage merely extracts the front end of the mandrel from the space between the mill rollers so as to permit the bloom and mandrel, once the mandrel has been ejected from the carriage, to be moved by the second lifting means on to the second guide.

On the second guide, the bloom is preferably withdrawn from the mandrel. The bloom and the mandrel are then conveyed separately, one behind the other, rearwardly of the carriage where the bloom is removed and the mandrel is cooled and placed on the first guide for re-use.

In this way the removal of the blooms does not lengthen the production cycle of the mill.

It is possible to use a large number of mandrels, which way be stored together on a bench between the first and second guides before being recycled. In this way each rod has time to cool and can be repaired during the cooling period.

In the drawings:

FIG. 1 is a diagrammatic plan view of a mill according to the invention,

FIG. 2 is a rear view in elevation of one of the bridge structures of the mill of FIG. 1, with parts removed for the sake of clarity,

FIG. 3 is a front view in elevation of the carriage and frame of the mill of FIG. 1, on a. larger scale,

FIG. 4 is a section on a reduced scale on the line IV--IV of FIG. 3, and

FIG. 5 is a plan view of the detail illustrated in FIGS. 3 and 4.

In FIG. 1, a mill 1 has at its front a perforating stand 2 inside which are arranged at least two barrel-shaped mill rollers 3 with crossed axes. They define a space at the forward end of the axis of the mill.

Behind the perforating stand 2 are at least one and preferably a plurality of identical bridge structures 4, disposed in alignment with the axis of the mill. The number of these structures depends on the length of the bars to be perforated.

Each bridge structure 4 comprises (FIG. 2) two lateral uprights 5 and 6 supporting a transverse upper member 7.

The transverse member 7 is provided with a central recess 8 that is concave downwards. The recess 8 is aligned with the axis of the mill and therefore with the space between the mill rollers 3.

The mill rollers 3 are adapted to cause a bar to advance towards the bridge structures 4, to be perforated axially by a mandrel 9 carried by a carriage 10 (FIG. 1). This carriage is slidably mounted on a frame 11 located behind the bridge structures 4 coaxially with them. The perforation of the bar produces a tubular bloom 12 which surrounds the mandrel 9 and, while being formed, advances below the bridge structures 4 and along the recesses 8.

For the purpose of supporting the tubular bloom l2 and the mandrel 9 inside their recesses 8, the bridge structures are each provided with three rollers 13 (FIG. 2) transversely displaceable by means of a known system of levers 14.

Below the bridge structures 4 and adjacent to their uprights 5 is a first roller guide 15 which is parallel to the axis of the mill and extends some distance behind the bridge structures 4 and the frame 11 and alongside a bench 16 (FIG. 1) located behind the frame 11.

Below the bridge structures 4 and adjacent the uprights 6 is a second roller guide 17 which also extends behind the bridge structures 4 and frame 11 alongside the bench 16, on the side opposite the first roller guide 15.

A first lifting arm 18 (FIG. 2), pivoted to the top of each upright 5, is movable in a plane transverse to the mill axis and is provided at its end with a roller 19 and a retaining extension 20 perpendicular to the arm 18 itself.

The length of the arms 18 is such that when each arm is in its vertically downwardly directed position, the

bottom end of the arm is at the same height as the first roller guide 15.

A mandrel 9 can travel on the roller guide 15. When the mandrel has reached a position in which its front end is substantially in contact with the perforating stand 2, the mandrel can be raised by the arms 18 into a position along the mill axis. The path of the mandrel during such movement is seen in ghost lines in FIG. 2.

The mandrel 9 is advanced on the roller guide by a motor (not illustrated), adapted to actuate at least one of the rollers of the guide 15. I

A second lifting arm 22 pivoted to the top of the upright 6 is also provided at its end with a roller 23 and a retaining extension 24. The length of the arm 22 is such that when the arm is in its raised substantially horizontal position the roller 23 it carries is immediately below the recesses 8. In this position the arm 22 can support a mandrel 9 and its surrounding tubular bloom when the mandrel and bloom are aligned with the axis of the mill. By rotating about its pivot, the arm 22 can transport the mandrel and bloom transversely as seen in ghost lines in FIG. 2 to deposit them on the second roller guide 17. The rollers of this guide 17 are rotated by motors 25 disposed outside the bridge structures 4.

From each upright 6 a horizontal extension 26 extends inwards and is articulated to an and of a vertically downwardly extending fluid cylinder 27. The other end of the rod of the cylinder 27 is pivoted to a yoke 28 at a point on the center line of the yoke.

The yoke 28 is pivoted at one end 28a to the bridge structure 4 and provided at the other end with a roller 29 located directly above the roller guide 17.

A vice 30 (FIG. 1) is arranged on the perforating stand 2 in alignment with the front end of the roller guide 17.

The carriage 10 located behind the bridge structures 4 is slidably mounted on the frame 11 by means of guides 31 (FIG. 3) of a known type and comprises a tubular body 32 provided with bore 33 which has at its front end a frusto-conical cavity or section 34. The section 34 is adapted to be coupled by pressure to a frustoconical section 35 (FIG. 4) on the rear end of each mandrel 9.

The carriage 10 is driven from the rear by a lever system 36 (FIG. 4) comprising a crank 37 pivoted to the rear end of the frame 11 and a connecting rod 38 pivoted between the end of the crank 37 and the rear end of the carriage 10. The crank 37 can be actuated by any suitable driving system so as to impart a reciprocating movement to the carriage 10.

A transverse projection 39 is arranged at an intermediate point onthe crank 37. A second connecting rod 40 is pivoted at its rear end to the end of the projection 39 and at its front end to the rear end ofa slider 41 in the form ofa rod mounted for sliding movement inside the bore 33.

The lengths of the slider 41 and connecting rods 38 and 40 are such that when the carriage 10 is in its extreme forward position, the free end of the slider 41 is inside the tubular body 32 and behind the frusto-conical section 34 of the bore 33; whereas when the carriage 10 is in its extreme rearward position, the free end of. the slider 41 is at least partly inside the frusto-conical section 34.

OPERATION OF MILL The manner of operation of the mill 1 is as follows:

A plurality of mandrels 9 are disposed on the bench 16 (FIG. 1) behind the frame 1 1 and parallel to the axis of the mill 1. That one of the mandrels 9 which is closest to the roller guide 15 is caused, by means known per se, to roll transversely on to the guide 15, along which it is advance axially until its front end is immediately adjacent the perforating stand 2.

In this position the mandrel 9 is lifted by the arms 18 until it is disposed coaxially inside the recesses 8 (FIG. 2).

When the mandrel 9 is in this position, the crank 37 (FIG. 4), which had previously been in the position shown in broken lines in FIG. 4, is rotated forward so as to advance the carriage 10, of which the bore 33 is coaxial with the mandrel 9.

When the carriage 10 advances, the tubular body 32 comes into contact with the mandrel 9, whose frustoconical end 35 engages inside the frusto-conical section 34 of the bore 33 and is thus axially connected to the carriage 10.

The carriage 10 causes the mandrel 9 to be pushed forward and its front end enters the space between the mill rollers 3.

A bar to be perforated now advances between the mill rollers 3 and comes axially into contact with the mandrel 9 between the mill rollers 3 and is axially perforated, progressively surrounding the mandrel 9.

When the bar is completely perforated and the tubular bloom 12 has been obtained, the crank 37 rotates rearwardly so that in a first stage the front end of the mandrel 9 is withdrawn from the space between the two mill rollers 3, and in a second stage the slider 41, advancing relatively inside the bore 33, detaches the mandrel 9 from the carriage 10.

At this point the mandrel 9 and the bloom surrounding it are engaged by the arms 22 (FIGS. 1 and 2) and transported transversely on to the roller guide 17.

When the mandrel 9 and the tubular bloom 12 reach the roller guide 17, the vice 30 grips the end of the mandrel 9 projecting from the tubular bloom 12, thus holding it against axial movement. At the same time the cylinders 27 lower the rollers 29 on to the tubular bloom 12, forcing it against the roller guide 17 and eliminating any possible relative sliding movement between the bloom 12 and the rollers of the guide 17. The motors 25 actuating the guide 17 therefore cause the bloom 12 to advance towards the bench 16 and be withdrawn from the mandrel 9. The bloom 12 travels along the whole of the guide 17 until it reaches a position beside the bench 16, where it is removed.

When the bloom 12 has been withdrawn from the mandrel 9, this mandrel is released by the vice 30 and the mandrel also can move axially on the roller guide 17 until it reaches the bench 16, where it is removed from the roller guide 17 and displaced transversely towards the roller guide 15 to begin a new cycle.

Since numerous mandrels 9 are stored on the-bench 16, after a working cycle each remains on that bench for a number of cycles equal to the number of mandrels stored there.

during the time for which they are out of action and during this period they can be repaired. These times comprising roller guides each of which extends have no effect on the operation of the mill. parallel to the mill axis adjacent said bridge struc- What I claim is: ture and extending some distance behind the car- I. In a perforating mill for forming tubular blooms, riage, vise means adjacent said mill rollers holding the mill comprising: 5 the mandrel against axial movement while it is sura. at least two mill rollers arranged with crossed axes r ded by the b oo of! e Sec d guide, and

and defining a space therebetween at the front end of the axis of the mill;

b. a carriage mounted behind the mill rollers, means further including means for moving the bloom along the second guide while the mandrel within it is gripped by the vice means, thereby withdrawing the bloom from the mandrel. 2. The mill of claim 1, including a bench located between the first and second guides behind the carfor connecting a mandrel disposed along the mill 10 axis to said carriage for movement therewith and means for moving said carriage between a forward position in which the mandrel is located in the space between the mill rollers and a rearward position in which the mandrel is located behind the mill rollers;

c. ejecting means for disconnecting the mandrel from the carriage when the carriage is in its rearward position;

d. a first guide means spaced away from the mill axis for supporting and transporting a mandrel;

e. a first lifting means for moving a mandrel from the first guide to a position along the mill axis for engagement by the carriage;

f. second guide means spaced away from the mill axis for supporting and transporting a bloom and a mandrel; and

g. second lifting means for moving a mandrel surrounded by a bloom to the second guide from a position along the mill axis when the carriage is in its rearward position and the ejecting means has disconnected the mandrel from the carriage, at least one bridge structure located between the mill rollers and the carriage, the bridge structure supporting the first and second lifting means each such lifting means comprising an arm pivoted at one end to the bridge structure and at the other end having a support roller and a retaining projection, the arms being movable in planes transverse to the mill axis, said first and second guide means mandrels transferred from the second guide to the bench for cooling before being transferred on to the first guide for re-use in the mill.

3. The mill of claim 1, in which the means to move the bloom along the second guide while the mandrel it contains is gripped by the vice means comprises a 20 motor arranged to drive at least one of the rollers of the second guide, at least one further roller located above the bloom and the second guide and bearing on the bloom, such further roller being supported in a yoke that is pivoted at one end to fixed structure and is acted 25 upon b a fluid cylinder to exert pressure on the bloom. e mill of claim 1, in which the carriage 1s slidable rectilinearly on a frame and including a crank rotatable about a fixed axis and connected to the carriage by a connecting rod, the crank having connected to itself at a point intermediate its ends a second connecting rod that is also connected to a slider that extends into a bore passing through the carriage, said slider comprising said ejecting means to eject the mandrel from the carriage when the crank is actuated to move the carriage into its rearward position.

5. The mill of claim 4, in which the mandrel has a frusto-conical rear end for engagement in a frusto-conical cavity in the carriage, means for guiding said slider into the frusto-conical cavity in the carriage when the carriage approaches its rearward position.

riage, the bench being adapted to support a plurality of I 

1. In a perforating mill for forming tubular blooms, the mill comprising: a. at least two mill rollers arranged with crossed axes and defining a space therebetween at the front end of the axis of the mill; b. a carriage mounted behind the mill rollers, means for connecting a mandrel disposed along the mill axis to said carriage for movement therewith and means for moving said carriage between a forward position in which the mandrel is located in the space between the mill rollers and a rearward position in which the mandrel is located behind the mill rollers; c. ejecting means for disconnecting the mandrel from the carriage when the carriage is in its rearward position; d. a first guide means spaced away from the mill axis for supporting and transporting a mandrel; e. a first lifting means for moving a mandrel from the first guide to a position along the mill axis for engagement by the carriage; f. second guide means spaced away from the mill axis for supporting and transporting a bloom and a mandrel; and g. second lifting means for moving a mandrel surrounded by a bloom to the second guide from a position along the mill axis when the carriage is in its rearward position and the ejecting means has disconnected the mandrel from the carriage, at least one bridge structure located between the mill rollers and the carriage, the bridge structure supporting the first and second lifting means each such lifting means comprising an arm pivoted at one end to the bridge structure and at the other end having a support roller and a retaining projection, the arms being movable in planes transverse to the mill axis, said first and second guide means comprising roller guides each of which extends parallel to the mill axiS adjacent said bridge structure and extending some distance behind the carriage, vise means adjacent said mill rollers holding the mandrel against axial movement while it is surrounded by the bloom on the second guide, and further including means for moving the bloom along the second guide while the mandrel within it is gripped by the vice means, thereby withdrawing the bloom from the mandrel.
 2. The mill of claim 1, including a bench located between the first and second guides behind the carriage, the bench being adapted to support a plurality of mandrels transferred from the second guide to the bench for cooling before being transferred on to the first guide for re-use in the mill.
 3. The mill of claim 1, in which the means to move the bloom along the second guide while the mandrel it contains is gripped by the vice means comprises a motor arranged to drive at least one of the rollers of the second guide, at least one further roller located above the bloom and the second guide and bearing on the bloom, such further roller being supported in a yoke that is pivoted at one end to fixed structure and is acted upon by a fluid cylinder to exert pressure on the bloom.
 4. The mill of claim 1, in which the carriage is slidable rectilinearly on a frame and including a crank rotatable about a fixed axis and connected to the carriage by a connecting rod, the crank having connected to itself at a point intermediate its ends a second connecting rod that is also connected to a slider that extends into a bore passing through the carriage, said slider comprising said ejecting means to eject the mandrel from the carriage when the crank is actuated to move the carriage into its rearward position.
 5. The mill of claim 4, in which the mandrel has a frusto-conical rear end for engagement in a frusto-conical cavity in the carriage, means for guiding said slider into the frusto-conical cavity in the carriage when the carriage approaches its rearward position. 